Controller for estimating relative humidity and condensed water, and method for controlling condensed water drain using the same
Abstract
The present invention provides a relative humidity and condensed water estimator for a fuel cell and a method for controlling condensed water drain using the same. Here, the relative humidity and condensed water estimator is utilized in control of the fuel cell system involving control of anode condensed water drain by outputting at least two of signals comprising air-side relative humidity, hydrogen-side relative humidity, air-side instantaneous or cumulative condensed water, hydrogen-side instantaneous or cumulative condensed water, instantaneous and cumulative condensed water of the humidifier, membrane water contents, catalyst layer oxygen partial pressure, catalyst layer hydrogen partial pressure, stack or cell voltage, air-side catalyst layer relative humidity, hydrogen-side catalyst layer relative humidity, oxygen supercharging ratio, hydrogen supercharging ratio, residual water in a stack, and residual water in a humidifier.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method for controlling condensed water drain using a relative humidity and condensed water estimator for a fuel cell, the method comprising:
calculating, by a controller, a residual amount of condensed water based on a water balance equation in an anode condensed water collector;
determining a condensed water level sensor is at a warning stage if the residual amount of condensed water is greater than a product of a density (ρ[kg/m{circumflex over ( )}3]) of condensed water and a total volume (V 1 [m{circumflex over ( )}3]) of the condensed water collector, and a duration thereof is greater than a reference value t 1 ;
determining the condensed water level sensor has failed if V_cell is smaller than V_cell_TH, ΔV_cell is greater than ΔV_cell_TH, hydrogen recycle blower RPM is smaller than RPM_cmd, anode stack inlet pressure is greater than an inlet normal pressure map plus P_TH, or anode stack outlet pressure is greater than an outlet normal pressure map plus P_TH, and a duration thereof is greater than a reference value t 2 ; and
performing a control of a condensed water drain valve based on an anode water trap (AWT) estimated value,
wherein V_cell, V_cell_TH, ΔV_cell, ΔV_cell_TH, RPM_cmd, and P_TH signify stack cell voltage, stack cell voltage lowest limit reference value, stack cell voltage deviation, stack cell voltage deviation upper limit reference value, hydrogen recycle blower RPM command value, and pressure difference acceptable reference value, respectively, and
wherein the residual amount of condensed water is calculated by the following equation:
Residual
condensed
water
[
kg
]
=
∑
t
=
0
t
=
∞
[
A
W
T
-
(
Anode
condensed
water
drain
valve
on
)
×
(
Condensed
water
outflow
per
second
)
]
×
Δ
t
+
Residual
condensed
water
initial
value
.
2. The method of claim 1 , wherein, upon drain valve control, if the residual amount of condensed water is greater than a product of the density (ρ[kg/m{circumflex over ( )}3]) of condensed water and a volume (V 2 [m{circumflex over ( )}3]) of the condensed water collector from the bottom thereof to a location of the water sensor, and the duration is greater than a reference value (t 3 ), a control for opening the condensed water drain valve is performed.
3. The method of claim 1 , wherein, upon drain valve control, if the residual amount of condensed water is smaller than a product of the density (ρ[kg/m{circumflex over ( )}3]) of condensed water and a value obtained by subtracting a condensed water difference acceptable reference value (V_TH) from a volume (V 2 [m{circumflex over ( )}3]) of the condensed water collector from the bottom thereof to a location of the water sensor, or a drain valve open duration is greater than a reference value (t 4 ), a control for closing the condensed water drain valve is performed.Cited by (0)
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